621941921 has 8 divisors (see below), whose sum is σ = 626192424. Its totient is φ = 617702400.

The previous prime is 621941911. The next prime is 621941939. The reversal of 621941921 is 129149126.

It can be written as a sum of positive squares in 4 ways, for example, as 25361296 + 596580625 = 5036^2 + 24425^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 621941921 - 2⁶ = 621941857 is a prime.

It is a super-3 number, since 3×621941921³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621941911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 132995 + ... + 137591.

It is an arithmetic number, because the mean of its divisors is an integer number (78274053).

Almost surely, 2^621941921 is an apocalyptic number.

It is an amenable number.

621941921 is a deficient number, since it is larger than the sum of its proper divisors (4250503).

621941921 is a wasteful number, since it uses less digits than its factorization.

621941921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5491.

The product of its digits is 7776, while the sum is 35.

The square root of 621941921 is about 24938.7634216294. The cubic root of 621941921 is about 853.5912283897.

The spelling of 621941921 in words is "six hundred twenty-one million, nine hundred forty-one thousand, nine hundred twenty-one".